Projection

Lambert azimuthal-equal area. Central latitude: 45° N, central longitude: 20° E. X, Y origin offset - 0

Datum: ETRS89

Sources

The physical map was made using the following public domain sources:

• Topography: NASA Shuttle Radar Topography Mission (SRTM30) data
  
• Shoreline, lakes and rivers: derived from Natural Earth data

Additional references for the map content:

• Tacitus, Germania (ca. 100)
• Ptolemy, Geographia (ca. 140)
• Atlante storico DeAgostini, Instituto Geografico DeAgostini, 1998. pg. 35-41.
• Historischer Weltatlas, Dr. Walter Leisering, Marix Verlag, 2011. pg. 26-27
• Történelmi világatlasz, Cartographia Kiadó, 2005. pg. 20-21.
• The Penguin Historical Atlas of Ancient Rome by Christopher Scarre, Penguin Historical Atlases, 1995. pg. 81.

Software used

GIS:

• Open JUMP GIS (open source): http://www.openjump.org/
• GRASS GIS (open source): http://grass.osgeo.org/

Graphics editors:

• Inkscape (open source): http://inkscape.org/
• GIMP (open source): http://www.gimp.org/